polüploidse

Polüploidne refers to an organism or cell that contains more than two sets of chromosomes. In a typical diploid organism, chromosomes exist in pairs, with one set inherited from each parent. However, polyploid organisms have three or more complete sets of chromosomes. This condition is particularly common in plants and can lead to significant changes in their characteristics, such as increased size, vigor, and altered flowering or fruiting patterns.

The process by which polyploidy occurs is called polyploidization. This can happen spontaneously through errors in cell division, specifically during meiosis or mitosis, where chromosomes fail to separate properly. Alternatively, it can be induced artificially, often through the use of chemicals like colchicine, which interfere with chromosome segregation.

Polyploidy can be classified by the number of chromosome sets present. Triploid organisms have three sets, tetraploid have four, pentaploid have five, and so on. Organisms with an even number of chromosome sets, like tetraploids, can often reproduce sexually because their chromosomes can pair up during meiosis. However, those with an odd number of sets, such as triploids, are often sterile due to difficulties in forming balanced gametes, leading to irregular chromosome distribution. Despite this, sterile polyploids can sometimes be propagated vegetatively.

In agriculture, polyploidy has been exploited to develop crops with desirable traits. For example, many cultivated fruits and vegetables, including strawberries, wheat, and potatoes, are polyploid. These naturally occurring or artificially induced polyploid varieties often exhibit improved yields and enhanced resistance to diseases. While less common in animals, some species, like certain fish and amphibians, also exhibit polyploidy.